Spark-plug.



1. P. INMAN & R. E. ESTES.

SPARK PLUG.

APPLICATION FILED NOV-1|, 1913- I I 1 ,136,961, Patented Apr. 27, 1915.

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, certain new and useful UNITED STATES PATENT OFFICE.

JOHN 1P. INMAN" AND ROBERT E. ESTES, OF MIDLAND, TEXAS.

SPARK-PLUG.

To all whom it-may concern:

Be it known that we, JOHN P. INMAN and ROBERT E.' '?E sjrns, citizens ofthe United States, residing atLMidIa-nd, in the county of Midland andState of Texas, have invented Improvements in Spark-Plugs, of which thefollowing is a specification.

Our invention relates to improvements in spark plugs, such as are usedin explosive engines, and one object of the invention is to providemeans whereby the electrodes of the spark plug maybe readily cleanedwhile the motor is running, and whereby the electrodes may be adjustedinto greater or less contiguity with each other, so as to thereby adjustthe distance across which the spark will jump.

A further object of the invention is to so construct the base of thespark plug that by removing the porcelain insulator and the bushingsupporting it, a tire pump may be connected with the plug base, thusdoing away with the necessity of removing the plug entirely from thecylinder of the engine and inserting the pipe of the tire pump inengagement with the screw threads of the cylinder. The reason for thisis that the engagement and disengagement of the tire.

pump pipe with the screw threads of the cylinder tends to wear the screwthreads in cylinder. The spark plug base, however, may be readilyremoved and replaced at any time if the threads are worn in plug base.

A further object of the invention is to provide a spark plug soconstructed as to permit gasolene or other liquid to be poured throughthe plug whereby to prime the motor or to clean the plug.

A still further object is to provide a plug of the character stated,very simply and cheaply constructed wherein all the parts are readilyremovable and replaceable.

Our invention is illustrated in the accompanying drawings, whereinFigure 1 is a longitudinal section of a spark plug constructed inaccordance with our invention. Fig. 2 is a perspective view of theelectrode pin." Fig. 3 is a perspective view of the cap supporting theelectrode pin and of the lock nut thereon.

Corresponding and like parts are referred to in the followingdescription and indicated in all the views of the accompanying drawingsby the same reference characters.

Referring to these drawings, 2 designates Specification of LettersPatent. P t t d Ap 27 1915 Application filed November 11, 1913. SerialNo. 800,282.

the plug base. The lower portion 3 of this base is cylindrical in formand exteriorly screw-threaded, as at 4. The upper portion 5 of the baseis also cylindrical in form but has an internal diameter equal to theexternal diameter of the portion 3. The upper portion of thebase isinternally screwthreaded as at 6. Engaging the upper portion of the baseis a clamp bushing 7 which is exteriorly screw threaded and formed witha head whereby it may be rotated. Fitting within the base 2 is theporcelain insulator 8 which is formed intermediate its ends withan-a'nnular flange or shoulder 9. The diameter of the flange or shoulderis equal to the interior diameter of the base. The insulator below theshoulder 9 has an interior diameter equal to the interior diameter ofthe portion 3 of the base while the upper portion of the insulator abovethe shoulder 9 is sufl'iciently smaller in diameter than the upperportion of the base 5 to permit the insertion of the bushing 7.

Mounted upon the upper end of the insulator is the cap or head 10. Thiscap is cylindrical in form and is provided intermediate its ends withthe annular flange 11 which fits upon the upper end of the insulator.The lower end of the cap fits into the annular recess formedin the upperend of the insulator. The cap is interiorly screw-threaded as at 12,these screw-threads extending the full length of the cap. Disposedwithin the insulator is the metallic sleeve 13, the upper end of whichis screw threaded for engagement with the lower end of the cap 10 andthe lower end of the sleeve is enlarged as at 14, the lower end of thehollow interior of the insulator being enlarged as at 15 to accommodatethis enlargement of the cap. A gasket 16 of copper or asbestos isdisposed between the flange 9 of Iighe insulator and the shoulder .17 ofthe ase.

Passing through the center of the sleeve 13 is the electrode pin 18which is enlarged at its upper end as at 19, this enlargement beingscrew-threaded to engage the screw threads 12 on the cap 10. Theelectrode pin 18 fits the sleeve 13 snugly and projects below the lowerend of the sleeve and its lower extremity is disposed in contiguity withthe.

electrode bar 20. This electrode bar and theelectrode pin are preferablymade of nickel. The upper end of the electrode pin is formed with a head21 having means whereby the electrode pin may be rotated, this meanspreferably being a notch or nick 22 extending transversely across theupper face of the head. A lock-nut 23 engages the screw threaded portion19 and bears against the upper end of the cap 10. This lock-nut ispreferably formed with laterally extending wings or prolongatlons sothat it may be readily manipulated without the necessity of using awrench. These wings permit the nut to be turnedby means of a stick orany like member of insulating material. The wires energizing theelectrode 18 are secured to the cap 10 by means of a clamp nut 25 whichengages the screw threads 26 formed upon the exterior of the upper endof the cap 10. hen the clamp nut 25 is turned down it binds theconducting wires between the clamp nut and the flange 11.

The particular object of forming the upper portion 5 of the base 2 withan interlor diameter equal to the exterlor d1ameter of the lower portion3 is to permit the pipe leading to a tire pump to be inserted in theplug base instead of havmg to remove the plug entirely from thecylinder. This obv1- ates the wear on the threads of the cylinder and itwill be obvious, also removes the necessity of entirely removing thespark plug in order to connect saidtire pump with the cylinder. 4

Vhile we do not wish to limit ourselves to the number of threads onthe'portion 19 of the electrode pin, preferably this pm has thirty-twothreads to the inch, so that one full turn of the electrode pin in oned1rection will give a gap between the lower end of the pin and the bar20 one thirty-second of an inch wide. To set spark gap at onesixty-fourth of an inch, the electrode pin 18 is turned half around. Itwill be understood that this ratio between the amount of rotativemovement of the pin and the gap between the lower end of the pin and thebar 20 may be changed to any extent desired. By adjusting the pin 18 inthe cap 10 the gap between the bar 20 and the lower end of the pin maybe accurately adjusted to any extent desired, and it is obvious alsothat the amount of this adjustment may be accurately determined by thenumber of rotations given to the head 21. Furthermore it will be obviousthat by rotating the pin so as to shift it downward andbring its lowerend into engagement with the projection 20 on the electrode bar 20 theplug can be cleaned while the motor is running. After the spark pointsare cleaned it is an easy matter to return the original position.

It will be seenthat the electrode pin 18 may be entirely removed fromthe plug and that when so removed, gasoleneor other liquid may be pouredthrough the plug into electrode to its the cylinder, thereby to clean orprime the motor or to clean the plug.

Gaskets 27 and 28 are disposed, the first under the nut at the upper endof the sleeve 13 and the other between the enlarged lower end of thesleeve and the shoulder on the insulator. These gaskets make a gas-tightjoint at all times andcompensate for the expansion and contraction ofthe sleeve. The gaskets are made of material having a greatercoefficient of expansion and contraction than the sleeve, and it willtherefore be obvious that the expansion and contraction of the sleeveand the gaskets are opposed.

\Vhile we do not wish to limit ourselves to the material from which theplug is made, we find in practice that it is best to make the base,bushing and cap, of iron or steel; the insulator of porcelain, and theelectrode pin or bar of nickel.

It is likewise to be noted that the insulating core 8 is easilyremovable from the base by simply removing the bushing 7, thuspermitting the ready introduction of a new insulator at any time.

It is to be noted that not only is the upper portion of the plug base ofthe same diameter as the internal diameter of the lower portion of theplug base, but the screw threads have the same pitch.

Having thus described the invention what is claimed as new is 1. In aspark plug, an insulator having a bore extending longitudinallytherethrough, a sleeve fitting the bore, the upper end of the sleeveextending beyond the upper end of the insulator, an electrode passlngthrough the sleeve, and a cap resting upon the upper end of theinsulator and engaging with the upper end of thevsleeve, havingindependent screw threaded engagement with the upper end of theelectrode.

2. In a spark plug, an insulator having a bore extending longitudinallytherethrough,

a sleeve screw-threaded at its upper end and enlarged at its lower endp'assingthrough said bore, a cap disposed upon the upper end of theinsulator and interiorly screw threaded to engage said sleeve, anelectrode pin passing through the sleeve and insulator and having .screwthreaded engagement at its upper end with said cap.

3. In a spark plug, an insulator having a bore extending longitudinallytherethrough, a sleeve screw-threaded at its upper end and enlarged atits lower end passing through said bore, a capdisposed upon the upperend of the insulator and interiorly screwthreaded to-engage said sleeve,an electrode pin passing through the sleeve and insulator and havingscrew-threaded engagement at its upper end with said cap, whereby theelectrode pin may be longitudinally adjusted with relation to the capand sleeve, and

means for locking the electrode pin in any adjusted position.

4. In a spark plug, an insulator having a longitudinally extending bore,a sleeve fitting said bore and having an enlarged lower end, the upperend of the sleeve being exteriorly screw-threaded, a cap on the upperend of the insulator having screw-threaded engagement with the sleeveand extending beyond the sleeve, an electrode pin passing through thesleeve and said cap, and having screw-threaded engagement with the cap,and means for locking the electrode pin in any desired position.

5. In a spark plug, a tubular insulator, a tubular sleeve disposedtherein, a tubular cap on the insulator, and an electrode pin passingthrough the sleeve and insulator and having screw-threaded engagement atits upper end with said cap said sleeve having screw threaded engagementwith the cap.

6. In a spark plug, a tubular insulator, a tubular member passingthrough the insulator and engagedtherewith against upward movement, anelectrodepin screw-threaded at its upper end, and a member mounted uponthe insulator through which the electrode pin passes and with which thescrew threads of the electrode pin have engagement, said member havingscrew threaded engagement with the first-named member whereby to permitthe electrode pin to be entirely removed from the insulator to therebypermit the introduction of liquids into the *7 cylinder through theinsulator.

7. In a spark plug, a tubular insulator having a central bore, the upperend of the insulator being recessed immediately surrounding the bore, acap mounted on the upper end of the insulator and having interior screwthreads, said cap extending down into the said recess, a sleeve disposedwithinthe insulator bore having an enlarged lower end, the upper end ofthe sleeve having screw-threaded engagement with the lower end of thecap, and an electrode pin having a smooth surface passing through thesleeve, the upper end of the electrode pin having screw-threadedengagement with said cap.

8. In a spark plug, a tubular insulator having a central bore, the upperend of the insulator being recessed immediately surrounding the bore, acap mounted on the upper end of the insulator, said cap extending downinto the said recess, a sleeve disposed within the insulator bore havingan enlarged lower end, the upper end of the sleeve having screw-threadedengagement with the lower end of the cap, an electrodepin having asmooth surface passing through the sleeve, the upper end of theelectrode pin having screw-threaded engagement with said cap, and alock-nut engaging the screw threaded portion of the pin and bearingagainst the upper end of the sleeve.

9. In a spark plug, a plug base enlarged at its upper end, the exteriorof the lower end being threaded to engage a compression chamber, theinterior of the upper end being threaded, a tubular insulator, the lowerend of which fits the lower end of the plug base, a clamp bushingengaging the insulator and the upper end of the plug base, a sleevedisposed within the insulator, a tubular cap upon the insulatorinteriorly screw threaded for its entire length, the upper portion ofsaid cap being exteriorly screw threaded, an electrode pin having asmooth surface for the greater portion of its length and passing throughthe sleeve, the upper portion of the pin being enlarged andscrew-threaded to engage the screw threads of the upper portion of thecap, a head on said electrode pin whereby it may be rotated, a lock-nutengaging the screw threads of the electrode and bearing against theupper end of the cap, and a wire clamp nut engaging said cap.

, 10. In a spark plug, an insulator having a central bore enlarged atits upper end, a tubular element disposed in the enlarged upper portionof the bore of the insulator, the interior diameter of said tubularelement being the same as the interior diameter of the contractedportion of said central bore, said tubular element being interiorlyscrewthreaded, and an electrode passing through the bore of theinsulator and having screw threads at its upper end engaging with saidtubular member, whereby to permit the removalof the electrode and permitthe introduction of liquid into the cylinder through the plug.

11. In a spark plug, an insulator having .a longitudinally extendingbore, a sleeve fitting said bore and having an enlarged lower end, a capon the upper end of the insulator having screw-threaded engagement withthe sleeve, an electrode pin passing through the sleeve and the cap, andgaskets disposed be; tween the cap and the insulator and between theenlarged end of the sleeve and the insulator, said gaskets having agreater coefficient of expansion and contraction than the sleeve andcap.

In testimony whereof we aifix our signatures in presence of twowitnesses.

JOI-Ih P. INMAN. [L. s.] ROBERT E. ESTES. [Ls] Witnesses: A. B. Es'rns,

D. W. BRUNSON.

